The present invention relates to a disc-clamping device for fixedly maintaining a disc on a turntable when the disc is inserted into a box of a disc device.
A conventional disc-clamping device is arranged higher than a disc-charging position opposing the turntable of the clamping member, and is adapted to fixedly maintain the disc between said clamping member and the turntable by lowering said clamping member or raising the turntable side after inserting a disc-loading tray into the disc device box.
However, one of the drawbacks of the above conventional disc clamping device is that disc device cannot be made narrower because said device arranges the clamping members by opposing them above and below the turntable and occupies a high percentage of the space in the upper and lower portions of the device box. Further, in order to secure the accuracy of the relative position of the clamping member and turntable, parts must be accurately assembled.
As a disc clamp mechanism for a disc play-back device which regenerates a disc such as a CD-ROM (compact disc) or the like, it is known that a disc is clamped onto a turntable with a magnet-type clamp member at the upper portion of the disc.
However, in the disc clamp mechanism of the conventional disc regenerative device, the clamp member is arranged over the disc, which makes the height of the disc regenerative device higher, thereby increasing the number of parts and complicating assembly of the device.
In addition, in the conventional disc clamp device, an elastic O-ring 51 is inserted around an outer side of a cylindrical axis 50a projected to the intermediate portion of the upper surface of the turntable as shown in FIG. 31 and lower end portions 52b of a guide member 52 having a plurality of ball holes 52a (e.g., 3 ball holes) equally distributed thereon, are forcibly inserted into the turntable 50 with said cylindrical axis 50a covered by said guide member 52.
A plurality (e.g., 3) of steel balls 53, 53, 53 are equally distributed to said ball holes 52a, respectively, and are elastically energized toward the outside by said O-rings 51.
However, since in the O-ring 51 the conventional disc clamp device loses its elasticity as time passes, the elastic force to the steel ball 53 gradually decreases. In addition, in the conventional disc clamp device, a separate step to forcibly insert the guide member 52 into the turntable 50 is required.